#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using lll = __int128_t;
using pii = pair<int, int>;
#define rep(i, a, b) for (int i = (a); i <= (b); i++)
#define per(i, a, b) for (int i = (a); i >= (b); i--)
#define endl '\n'
const int N = 1e3 + 5;
const int M = 2e5 + 5;
const int INF = 1e6;
int n, m, s, t;
ll x[N], y[N];
int head[N];
int ver[M], W[M], Next[M], tot = 1;
void add(int u, int v, int w) {
  ++tot;
  ver[tot] = v;
  W[tot] = w;
  Next[tot] = head[u];
  head[u] = tot;
}
void addedge(int u, int v) {
  add(u, v, 1);
  add(v, u, 0);
}
int dep[N];
bool bfs() {
  rep(i, 1, t) dep[i] = 0;
  queue<int> q;
  q.push(s);
  dep[s] = 1;
  while (q.size()) {
    int u = q.front();
    q.pop();
    for (int i = head[u]; i; i = Next[i]) {
      int v = ver[i];
      int w = W[i];
      if (w && !dep[v]) {
        dep[v] = dep[u] + 1;
        q.push(v);
      }
    }
  }
  return dep[t];
}
int dfs(int u, int in) {
  if (u == t) return in;
  int out = 0;
  for (int i = head[u]; i; i = Next[i]) {
    int v = ver[i];
    if (dep[v] == dep[u] + 1 && W[i]) {
      int flow = dfs(v, min(W[i], in));
      out += flow;
      in -= flow;
      W[i] -= flow;
      W[i ^ 1] += flow;
      if (!in) break;
    }
  }
  if (!out) dep[u] = 0;
  return out;
}
int dinic() {
  int res = 0;
  while (bfs()) {
    res += dfs(s, INF);
    if (res >= INF) break;
  }
  return res;
}
lll dist(int i, int j) {
  lll dx = x[i] - x[j];
  lll dy = y[i] - y[j];
  return dx * dx + dy * dy;
}

bool check(lll d) {
  rep(i, 1, n * 2 + 2) head[i] = 0;
  tot = 1;
  rep(i, 1, n) rep(j, 1, n) if (dist(i, n + j) <= d) addedge(i, n + j);
  rep(i, 1, n) addedge(s, i);
  rep(i, 1, n) addedge(n + i, t);
  return dinic() == n;
}

int main() {
  ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);
  cin >> n;
  rep(i, 1, n * 2) cin >> x[i] >> y[i];
  s = n * 2 + 1, t = n * 2 + 2;
  lll l = 1, r = 2 * (lll)1e18 * (lll)1e18;
  while (l < r) {
    lll mid = (l + r) / 2;
    if (check(mid))
      r = mid;
    else
      l = mid + 1;
  }
  cout << fixed << setprecision(10) << sqrtl((long double)r);
  return 0;
}